- #1
Moranovich
- 10
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1. Homework Statement
a) Calculate the theoretical diameter of pipe, nominal pipe diameter and mean velocity of nominal pipe diameter.
Maximum velocity = 1.8m/s
Q(vol. flow rate) = 0.01M^3-1
b) Find the Reynolds number for the process and then the head loss due to friction, state any assumptions made.
Please see attached diagram***
2. Homework Equations
D=sqrrt 4*q/Pi*U
q=volumetric flow rate
D=theoretical diameter
Q=V*A
V=Q/A
V=mean velocity
A=cros sect area
Q=vol. flow rate
Re=um*d*P/U
Where um=mean velocity
d = diameter of pipe
p = density
U = dynamic viscosity of fluid
Re= Reynolds number
Head loss due to friction Hf=32*U*L*um/P*g*d^2
U = dynamic viscosity of fluid
L length of pipe from the pump = 27m
P= density taken from previous questions I have done for oil= 860Kgm-3
g = gravity 9.81m/s
d = diameter of theoretical pipe =120mm
3. The Attempt at a Solution
I have worked out the theoretical diameter to be 120mm from the first equation assuming that the mean velocity is roughly half the maximum velocity ie 0.9m/s
So sqrrt 4*q/Pi*U = sqrrt 4*0.01/3.142*0.9=0.12m
Then choosing from the table nominal pipe 100mm the actual velocity for the nominal pipe is 1.27m/s using this eq.
Q=V*A
V=Q/A
V=0.01/7.85*10^-3=1.27m/s
To work out the Reynolds number I have used the density and dyn. viscosity from previous questions (860kgm & 0.032)
Re=0.9*0.12*860/0.032=2902.5
To work out the head loss I have used these density and dyn. Viscosity figures again and worked out from the diagram that (from the pump) the length of pipe is 27M.
So Hf=32*0.032*27*0.9/860*9.81*0.12^2=0.205M
So head loss due to friction is 0.205M.
I am not sure if I should use these assumptions i.e density and viscosity that are not given in the question. Am I on the right track or away on a crazy tangent??!
Any help would be much appreciated – thank you in advance.
Cheers
a) Calculate the theoretical diameter of pipe, nominal pipe diameter and mean velocity of nominal pipe diameter.
Maximum velocity = 1.8m/s
Q(vol. flow rate) = 0.01M^3-1
b) Find the Reynolds number for the process and then the head loss due to friction, state any assumptions made.
Please see attached diagram***
2. Homework Equations
D=sqrrt 4*q/Pi*U
q=volumetric flow rate
D=theoretical diameter
Q=V*A
V=Q/A
V=mean velocity
A=cros sect area
Q=vol. flow rate
Re=um*d*P/U
Where um=mean velocity
d = diameter of pipe
p = density
U = dynamic viscosity of fluid
Re= Reynolds number
Head loss due to friction Hf=32*U*L*um/P*g*d^2
U = dynamic viscosity of fluid
L length of pipe from the pump = 27m
P= density taken from previous questions I have done for oil= 860Kgm-3
g = gravity 9.81m/s
d = diameter of theoretical pipe =120mm
3. The Attempt at a Solution
I have worked out the theoretical diameter to be 120mm from the first equation assuming that the mean velocity is roughly half the maximum velocity ie 0.9m/s
So sqrrt 4*q/Pi*U = sqrrt 4*0.01/3.142*0.9=0.12m
Then choosing from the table nominal pipe 100mm the actual velocity for the nominal pipe is 1.27m/s using this eq.
Q=V*A
V=Q/A
V=0.01/7.85*10^-3=1.27m/s
To work out the Reynolds number I have used the density and dyn. viscosity from previous questions (860kgm & 0.032)
Re=0.9*0.12*860/0.032=2902.5
To work out the head loss I have used these density and dyn. Viscosity figures again and worked out from the diagram that (from the pump) the length of pipe is 27M.
So Hf=32*0.032*27*0.9/860*9.81*0.12^2=0.205M
So head loss due to friction is 0.205M.
I am not sure if I should use these assumptions i.e density and viscosity that are not given in the question. Am I on the right track or away on a crazy tangent??!
Any help would be much appreciated – thank you in advance.
Cheers